Santos Medina appeals from Judge Werker’s order denying his motion to dismiss count two of a three count indictment or, alternatively, to exclude certain evidence in a possible subsequent prosecution. Medina was tried before Judge Werker and a jury in December 1982. He was charged with conspiracy to rob a bank, 18 U.S.C. §§ 371, 2113(a) (count 1), aiding and abetting a bank robbery, 18 U.S.C. §§ 2, 2113(a) (count 2), and aiding and abetting an armed bank robbery, 18 U.S.C. §§ 2, 2113(d) (count 3). The jury acquitted Medina on counts one and three, but was unable to reach a verdict on count two. Following the verdict, the district court declared a mistrial, and Medina then submitted the motion to which we have referred.
We affirm the order for the reasons stated in Judge Werker’s thorough opinion. 563 F.Supp. 979 (S.D.N.Y. 1983). Medina cannot demonstrate “that the issue he seeks to foreclose was ‘necessarily’ resolved in his favor in the first verdict,” and accordingly, he may not successfully invoke the collateral estoppel component of the Double Jeopardy Clause. United States v. Seijo, 537 F.2d 694, 697 (2d Cir.1976), cert. denied, 429 U.S. 1043, 97 S.Ct. 745, 50 L.Ed.2d 756 (1977).**
Our dissenting brother misconstrues the doctrine of collateral estoppel and its application to the case of a criminal defendant who attempts to preclude reprosecution of a count on which the initial jury was unable to reach a verdict. As noted in the text, our decisions, which the dissent fails to discuss, have established the principle that the defendant bears the burden of proving the first verdict necessarily determined in his favor the issues he seeks to foreclose from the jury’s consideration on retrial. United States v. Seijo, 537 F.2d 694, 697 (2d Cir.1976), cert. denied, 429 U.S. 1043, 97 S.Ct. 745, 50 L.Ed.2d 756 (1977); United States v. Cala, 521 F.2d 605, 608 (2d Cir.1975). Moreover, this burden “is a heavy one,” United States v. Seijo, supra, 537 F.2d at 697, because of the great difficulty of proving the basis for the jury’s verdict. Id.; United States v. Clark, 613 F.2d 391, 400 (2d Cir.1979), cert. denied, 449 U.S. 820, 101 S.Ct. 78, 66 L.Ed.2d 22 (1980).
In the present case, the jury could reasonably have acquitted Medina on count 3 because it believed the government had not sustained its burden of demonstrating appellant knew firearms would be employed in the robbery. Although it was undisputed the robbers were armed, there was no direct evidence indicating Medina was aware of this fact. Accordingly, the jury could have concluded Medina had not been proven guilty of aiding and abetting an armed robbery of a bank without resolving any of the essential elements of count 2.
*157Although as the dissent correctly notes, an examination of the court’s charge to the jury may help elucidate the basis for the verdict, see Ashe v. Swenson, 397 U.S. 436, 444, 90 S.Ct. 1189, 1194, 25 L.Ed.2d 469 (1970), such examination must be of the charge as a whole, not of incomplete excerpts which, standing alone, may be misleading. Judge Werker specifically noted the elements required for a conviction on an armed robbery charge, beyond those necessary for the lesser offense of bank robbery:
In order to convict the defendant on Count three, you must find that the government has proved beyond a reasonable doubt all of the elements of the crime charged in Count two. In addition, you must find beyond a reasonable doubt that the defendant in committing or attempting to commit this crime either assaulted or put in jeopardy the life of a person by the use of a dangerous weapon or device. Count three requires a finding that the defendant either: 1, assaulted a person by the use of a dangerous weapon or device; or 2, [e]ndangered the life of a person by the use of a dangerous weapon or device.
After being instructed in this manner, the jury could have determined the government had not proved these elements, required for a conviction on count 3, but not relevant to the lesser charge on count 2. Accordingly, there is no basis for concluding the jury’s verdict of acquittal on count 3 “necessarily” resolved in Medina’s favor any elements necessary for a conviction on count 2. Judge Werker properly denied Medina’s motions.